Coding apparatus



June 25, 1940- w. P. PLACE 2,205,909

coDlNG APPARATUS Original Filed Feb. 17. 1939 INVENTOR Uz'lldr' P. Place. Hg. 4. EY l HIS ATTORNEY Patented June 25, 1940 UNITED STATES PATENT OFFICE CODING APPARATUS Willard P. Place, Wilkinsburg, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania.

8 Claims.

particularly to coding apparatus comprising a code transmitter having contacts and means for periodically operating said contacts in a predetermined sequence.

The present application is a division of my copending application for Letters Patent, Serial No. 256,946, filed February 17, 1939, for Signal systems.

I shall describe one form of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

Code signal systems using recurrent impulses of direct current have been proposed for railways. Direct current from a convenient source such as a battery is periodically interrupted at different code frequencies or rates, code frequencies of 189, 129 and 75 cycles per minute being those generally used. The individual direct current impulses are of relatively high peak voltage and of a short duration. That is, the duration of the impulse is short as compared with the duration of the cycle period. For example, in the 12) code each code cycle period is of onehalf second duration and the duration of an individual current impulse would preferably be of the order of one hundredth second. Impulses of such short duration serve to limit the output from the battery to a low energy level. In such signal systems a code following relay is operated by the coded current to a first position when current flows and to a second position when the current ceases. Hence the period the relay remains in the position effected by the presence of current on period) is short as compared with the period the relay remains in the position (oif period) effected by the absence of current because the impulses are of short duration as compared with the duration between successive impulses. The decoding apparatus governed by the code following relay for selectively controlling sonic signal device in accordance with the different codes is ordinarily of such construction that most satisfactory operation is obtained when 'the code following relay is operated with substantially equal on and off periods.

Accordingly, a feature of my invention is the provision of novel and improved coding apparatus wherewith impulses of direct current corresponding to the different code frequencies or rates are supplied in such a manner that a code following relay operated thereby is operated with substantially equal on and olf periods. Other features and advantages of my invention will appear as the specification progresses.

My invention relates to coding apparatus, and

For a better understanding of my invention reference can be had to the accompanying drawing in which Fig. 1 is a view partly diagrammatic and partly in plan showing a coder or code transmitter embodying my invention. Fig. 2 is a de- 5 tail of the coder of Fig. 1. Fig. 3 is a diagram illustrating the operation of certain circuit controlling contacts of the coder of Fig. 1. Fig. 4 is a diagram illustrating operating characteristics of the current impulses created by the coder 10 of Fig. l. In each of the several views like reference characters designate similar parts.

Code transmitters of the torsional type are well known. For example, the code transmitter of the general construction covered by the Unit- 15 ed States Letters Patent No. 1,858,876, granted May 17, 1932, to Paul N. Bossart for Coding apparatus, has been found satisfactory. My present invention is an improvement on code transmitters of the torsional type such as covered by 20 the above Bossart Patent No. 1,858,876.

Referring to Fig. 1, a magnetic core structure '29 is mounted on a frame 39 of suitable nonmagnetic material such as brass. The core 29 terminates in two spaced pole pieces 29a and 29h 25 and has mounted thereon a winding 3|. An armature 32 is secured to a shaft 33` in any convenient manner here shown as by set screw 32a.

in a hub of the armature. Shaft 33 is journaled in frame 39 so that the armature 32 is disposed for k3() rotatable movement between the pole pieces 29a` and 29D. The armature 32 is cylindrical in shape and is provided with an outer surface (see Fig.

2l) so shaped that when the armature is rotated in a rst direction (counterclockwise in Fig. 2) 35 from a normal or biased position the air gaps between the outer surface of the armature and the pole pieces 29a and 29h are gradually decreased, but if the armature is rotated in the opposite or second direction (clockwise in Fig. 2) 40 from such normal position the air gaps are at v first gradually increased and then abruptly increased. The armature 32 is biased to its normal position by a spiral spring 34 the outer end of which is secured to the frame 39 by screws 35 45 and its inner end to the hub of armature 32 by screws 196. The coder is provided with a contact Kl for controlling the supp-ly of current to winding 3l and which contact comprises a contact member 39 disposed for operation by rotation 50 of shaft 33, and a stationary contact member 31, the arrangement being such that contact p member 36 engages contact member 3'! to close the contact Kl at the normal position of armature 32 and the contact member 35 moves out 55 of engagement with contact member Si to open the contact Kl when the armature 32 swings in its first direction away from the normal position. The contact member .it is connected with a terminal 3S through a suitable flexible connection 33a, while the contact member 3l? is connected with one terminal of winding Si. When a source of direct current is connected at terminals B and C of Fig. l, the winding 3l is energized and a magnetic flux is built up in the core il@ which attracts armature t? against the force of the bias spring Sil in its first direction from its normal position, that is, armature 32 swings in the direction of the decreasing air gap. After a limited rotation of armature 32, the contact Ki is opened and the winding 3l is deenergized. Bias spring 35i now causes armature 32 to swing back toward its normal positio-n and contact Kl is closed to again energize winding 3l. Due to the inertia of the parts, armature til swings past the normal position in its second direction a limited distance before it is again rotated in its first direction due to the attraction created by the energization of winding 3i. The parts are so constructed that armature 32 swings substantially equal distances each side of its normal position. It is clear that as long as the current source is connected at terminals E and C the armature 32 will oscillate at a frequency governed by the mass of the armature 32 and the stiness of the spring E43. For example, the parts may be so proportioned and adjusted that armature oscillates at the frequency of 180 cycles per minute or at the frequency of 120 cycles per minute or at the frequency of 75 cycles per minute.

A contact is carried on shaft 33 by means of clips Contact Mil is preferably of the liquid ow type such as a mercury switch, a common construction of which consists of a glass envelope having two spaced metal electrodes and' a quantity of mercury sealed therein, the a1- rangement being such that the mercury bridges the electrodes at certain positions of the envelope and the mercury ows away from the electrodes when the envelope is tilted. In the embodiment here contemplated, contact Mil is so positioned on shaft 33 that the contact is closed at the nor- Ymal position of the armature and is tilted to open the contact as the armature swings in its first direction, and is reclosed as the armature swings back to its normal position and remains Iclosed while the armature swings in its second direction.

Hence, as illustrated in` Fig. 3, where the black area represents the closed position of the contacts, contact Mil opens at the start of each operating cycle of the coder (armature starts to swing in said one direction), is reclosed at the end of the rst half period of the cycle (armature returned to normal position) and remains closed during the second half period of each operating cycle (armature swings in said second direction and returns to normal position).

Again referring to Fig. l, a second armature fill is xed on a hollow shaft fil which is slipped over and rotates freely on shaft 33. Armature Il@ is joined to the shaft 33 through a spiral spring All, the outer end of spring il being secured to armature t@ through an l.shaped member [l2 bolted to armature lill at i3 and secured to the spring 4i at dll. The inner end of spring vil is secured to a sleeve 55, which sleeve is in turn secured to the shaft 33 by a set screw llt.

AAs here shown, three contacts` Ml, M2 and M3 behind armature 32.

are mounted on the hollow shaft ill through the medium of suitable clips lll. Contacts M, M2 and Mii are preferably of the liquid ilow type similar to contact Mil. An electromagnet i9 normally energized by any convenient source of current such as a battery iii) dampens the motion of armature it by induction with the outer rim ma of the armature llo, the outer rim of the armature passing between spaced pole pieces of magnet fill, as will be readily understood by an inspection of Fig. l.

lt is clear that when armature 32 is oscillated the hollow shaft il and armature Gill are also oscillated because of the connection effected by spring ill. The motion of armature lil lags the motion of shaft 33 and armature 32 by an amount depending upon they mass of armature lit, the stiffness of spring ill and to a small extent by the damping of magnet lll. If spring 4l is a stiff spring, armature lil will lag only a few degrees If spring All is weak, the lag of armature til becomes greater. The actual amount of lag can be readily controlled by adjusting the stiiness of spring di. Magnet 49 produces damping which increases with increasing velocity of armature fill, the latter damping being desirable to prevent the amplitude of the oscillation ofarmature all from becoming too great. It is obvious that the magnetic damping produced by magnet ci? can be replaced by varies mounted on the outer rim of armature i0 to increase its air resistance.

As illustrated in Fig. 3, contacts Ml, M2 and M5 of the present embodiment of the invention are mounted in a position so that contacts Mi and M3 are closed and contact M2 is open at the start of each operating cycle, that is, at the normal position of the armature 32. As armature 32 swings in its first direction away from the normal position, contact Ml is tilted swings back to its normal position to complete Vthe first half or on period of the cycle and then swings in its second direction, the contacts M3 and Mi are not reclosed and contact M2 is not again opened until predetermined positions are reached in the second half period of the operating cycle of the armature 32 because of the lag of armature lill. I have found that with the construction describedabove contacts M, M2 and M3 can be made to accurately and reliably open and close at selected positions in the operating cycle of the coder.

It is clear that with contacts Ml, M2, M3 and Mil operated during each operating cycle of the coder in the predetermined sequence pointed out above, circuits can be` controlled in such a man.- ner as to provide impulses of current at predetermined points of the operating cycle. It is also obvious that a coder constructed in accordance with my invention permits almost any desired sequence in the operation of a plurality of contacts to be effected.

The utility of coding apparatus which includes contacts and means for operating the contacts in a preselected manner is fully explained in my aforementioned copending application Serial No. 256,946 of which the instant case is a division. It is sufficient for the present case to point out that with contacts Ml and M3 closed circuits are completed for connecting a battery to the primary Winding of a first and a second transformer, respectively, and magnetic `'energy is built up in such transformer, the time constant of the circuits being preferably such that energy builds up relatively slow and little if any energy is inductively transferred to 'the secondary winding of the respective transformer. Contact Ml completes a rst circuit connection for the secondary winding of the first transformer to a transmitting circuit such, for example, as a track circuit, and contact M2 completes a second connection for the secondary winding of the second transformer with such track circuit. Looking at Fig. 3, it follows that at the start of an operating cycle energy is stored in the magneticI circuits of the first and second transformers because both contacts M3 and M4 are closed. Also, the secondary winding of the first transformer is connected with the track circuit because contact Ml is closed, but the secondary winding of the second transformer is disconnected from the track circuit because contact M2 is open. Just after the start of an operating cycle, con-tact M4 is opened, interrupting the circuit to the primary winding of the first transformer and the energy stored in the first transformer dies away, the decay being rapid and an electromotive force of relatively high peak voltage induced in the secondary winding of the first transformer so that a current impulse of corresponding magnitude is supplied to the track circuit. This current irnpulse may be of only one-half cycle duration or it may have a damped wave forni because of the oscillatory nature of the track circuit. The important feature of such impulse, as far as my present invention is concerned, is the fact that the impulse occurs at substantially the start of the operating cycle. That is to say, the impulse occurs at a preselected point of the operating cycle. Just after the first impulse ceases, contact Mi opens to disconnect the secondary winding of the first transformer from the track circuit and shortly thereafter contact M2 closes to complete the circuit of the secondary winding of the second transformer with the track circuit. At a predetermined later point of the first half period (on period) of the operating cycle, contact M3 is opened to interrupt the circuit to the primary winding of the second transformer and the energy stored in that transformer dies away rapidly to induce an electromotive force in the secondary winding of the second transformer so that a second current impulse is supplied to the track circuit, such second current impulse being similar to the first impulse. Consequently, as illustrated in Fig. 4, two current impulses are supplied to the track circuit during the on period of each operating cycle of the coder. These two current impulses occur at points of the first half period of the operating cycle predetermined by the setting of the contacts Mi, M2, M3 and M4. In other words, the two current impulses are spaced apart at a predetermined time interval by the setting of the contacts of the coder.

The code following relay receiving energy from such track circuit is therefore supplied with two energizing impulses each on period of the code cycle. 'It is clear that by proper spacing of the two current impulses the energization of the relay effected by the second impulse occurs just as the energization effected by the first impulse begins to die away, with the result that the relay is retained at the position corresponding to that effected by the presence of current for substantially the full first half period of the operating cycle. Hence, the code following relay is operated with substantially equal on and olf periods because of the spacing of the two current vimpulses during the on period of the code cycle.

If the coder is to be used in a circuit `supplying impulses of the 75 code rate the setting of the contacts would be such that the two current impulses are spaced slightly further apart than would be the case when the coder is usedwith a circuit supplying current impulses of the 120 code rate.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and mcdiiications may be made therein within the scope o the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

i. In a code transmitter having an armature fixed on a shaft for rotation and biased by spring means to a normal position about which it oscillates at a pre-selected frequency when the magnet of the code transmitter is supplied with current over a circuit including a contact operated by movement of the armature in a predetermined direction away from said normal position, the combination comprising, a member mounted in axial alignment with said shaft for rotation, resilient means to connect said member with said shaft to cause said member to oscillate with said armature with a predetermined lag, a first coding Contact mounted for operation by said armature and shaft, and a second coding contact mounted for operation by said member, a predetermined time interval after said first coding contact is operated.

2. In a code transmitter having an armature fixed on a shaft for rotation and biased by spring means to a normal position about which it oscillates at a preselected operating cycle when the magnet of the code transmitter is supplied with current over a circuit including a contact operated by movement of the armature in a predetermined direction away from said normal position, the combination comprising, a member mounted in axial alignment with said shaft for rotation, means including a spiral spring to connect said member with said shaft to cause said member to oscillate at said operating cycle with said member lagging said armature in a predetermined manner,a first coding contact operated by said armature at a preselected point of the operating cycle, and a second coding contact operated by said member at another preselected point of the operating cycle.

3. In a code transmitter having an armature fixed on aiirst shaft for rotation and biased by spring means to a normal position about which it oscillates at a preselected operating cycle when the magnet of the code transmitter is supplied with current over a circuit including a Contact operated by movement of the armature in a predetermined direction away from said normal position, the combination comprising, a hollow shaft adaptable of loose mounting on said first shaft, means including a spiral spring to connect said hollow shaft with said first shaft to cause said hollow shaft to oscillate at said operating cycle with a predetermined lag with respect to said armature, and a coding contact operated by said hollow shaft at a preselected point in the operating cycle.

4. In a code transmitter having a first armature fixed on a first shaft for rotation and biased by spring means to a normal position about which it oscillates at a preselected frequency when the magnet of the code transmitter is supplied with current over a circuit including a contact operated by movement of said armature in a predetermined direction away from said normal position, the combination comprising, a hollow shaft adaptable of loose mounting on said first shaft, a second armature fixed on said hollow shaft, means including a spring to connect said hollow shaft with said first shaft to cause said hollow shaft and second armature to oscillate when said first arma'- ture is oscillated with said hollow shaft and second armature lagging said first armature, means mounted for magnetic relationship with said second armature to control in part the lagging of said hollow shaft and second armature, and a coding contact operated by the movement of said hollow shaft and second armature.

5. In a codetransmitter having a first armature fixed on a first shaft for rotation and biased by spring means to a normal position about which it oscillates at a preselected operating cycle when the magnet of the code transmitter is supplied with current over a circuit including a contact operated by movement of said armature in a predetermined direction away from said normal position, the combination comprising, a hollow shaft adaptable of loose mounting on said rst shaft, a second armature fixed on said hollow shaft, resilient means to connect said hollow shaft with said first shaft to cause said hollow shaft and second armature to oscillate at said preselected operating cycle with said hollow shaft and second armature lagging said first armature, means mounted for magnetic relationship with said second armature to control in part the lagging of said hollow shaft and second armature, a rst coding contact operated by said armature at a preselected point of the operating cycle, and a second coding contact op'erated by said hollow shaft and second armature at another preselected point of the operating cycle.

6. In combination, a magnet having a winding and two spaced poles, a cylindrical armature fixed on a first shaft and mounted for rotation between said poles, spring means to bias said armature to a normal position, a Contact mounted on said shaft normally closed and adaptable of bec-pened when said armature rotates in a predetermined direction from said normal position, means including said contact for supplying current to said winding to cause said armature to oscillate at a frequency predetermined by 'its mass and by the stiffness of said spring means, a hollow shaft adaptable of loose mounting on said first shaft, means including a spring to connect said hollow shaft with said first shaft to cause said hollow shaft to oscillate with said armature with a predetermined lag, and another contact operated by said hollow shaft.

7. In combination, a magnet having a Winding and two spaced poles, a rst cylindrical armature fixed on a first shaft and mounted for rotation between said poles, spring means to bias said armature to a predetermined normal position, a contact controlled by said armature and adaptable of being opened when said armature oscillates in a predetermined direction from said normal position, means controlled by said contact for energizing said winding to cause said armature to oscillate at a frequency predetermined by its mass and the resiliency of said spring means, a hollow shaft adaptable of being slipped over said first shaft, a second cylindrical armature fixed on said hollow shaft, means including a spiral spring to connect said second armature with said rst shaft to cause said second armature and hollow shaft to oscillate when said first armature is oscillated with said second armature and hollow shaft lagging said first armature a predetermined degree, another contact operated by said hollow shaft, and magnetic means to control in part the lagging of said second armature.

8, In combination, a first armature xed on a first shaft for rotation, spring means to bias said armature to a predetermined normal position, motor means to operate said armature in a given direction, circuit means including a contact operated by movement of said armature to cause said armature to oscillate at a frequency predetermined by the mass of the armature and resiliency of said spring means, a hollow shaft adaptable of being slipped over said rst shaft, a second armature fixed on said hollow shaft, means including a spiral spring to connect said second armature to said first shaft to cause said hollow shaft and ,second armature to oscillate at said predetermined frequency when said first armature is oscilated with a lag predetermined by the resiliency of said spiral spring, magnetic means mounted for magnetic relationship with said second armature to dampen the movement of said second armature and first and second coding contacts mounted on said rst and hollow shafts respectively for operation a predetermined time interval apart.

WILLARD P. PLACE. 

